Fluid gage apparatus



Jan. 29, 1957 F. MEYER, JR

FLUID GAGE APPARATUS 2 Sheets-Sheet l Filed June 7, 1952 ATTORNEYS Jan.29, 195? F. MEYER, JR 2,779,188

FLUID GAGE APPARATUS Filed June 7. 1952 2 Sheets-Sheet 2 57 56 Tia-5- Vif ATTO R N EYS '2,779,iss

FLUID GAGE APPARATUS Franklin Meyer, Jr., Forestdale, R. I'., assignorto The Taft-Peirce Manufacturing Company, Woonsocket, R. I., acorporation of Rhode Island Application June 7, 1952, Serial No. 292,344

6 Claims. (Cl. 73-37.8)

The present invention rclates'to gaging apparatus of the general typeemploying the principle of uid escape from an orifice into a spacedetermined by the orifice and a juxtaposed surface of the article beingchecked. It is particularly concerned with a gaging apparatus whichutilizes such principle or phenomena in a novel manner such as toproduce an immediate direct reading or indication of the relation toeach other of certain surfaces such as in the checking of articles foraccuracy of taper, center distances, the squareness between the face andthe bore, the concentricity of alignment of two parts and likeconditions or articles where the matter f determining the relationbetween certain surfaces or portions of an article is the primeobjective.

The problem of providing a satisfactory means for the purpose has beencomplicated by the fact that there are always involved variables otherthan the particular factor to be tested or determined. For example, thematter of absolute dimensions enters into the results. Accordingly ithas normally in the past been necessary to employ at least two aircircuits and a like number of indicators for determining independentlythe respective dimensions and then the operator by adding or subtractingthe readings from the two or more indicators may compute the finaldesired answer. This computation has been required, for example, inchecking tapered parts where the diameters may vary in addition tovariations in the degree of taper. Similarly such computations wouldnormally be necessary in checking center distances between holes andclearances between mating parts. Even in cases where it may not benecessary to obtain results from separate indica-tors and compute ananswer as, for example, in checking the concentricity between diameters,nevertheless due to common permissible variations in diameter in suchcases the position of the tolerance range on a normal scale will change,since the diameter will affect the final reading.

The apparatus of the present invention is adapted to provide a directand accurate reading of the relation desired to be checked and to avoidthe complications and likely human errors indicated to some extentabove. The apparatus combines effectiveness and dependability with amarked simplicity of design and parts.

The principles and the construction and operation may be more readilyunderstood and appreciated from a specific application thereof asillustrated herein. Accordingly the invention comprises the features ofconstruction, combination of elements and arrangement of parts whichwill be exemplified in the particular apparatus hereinafter describedand the scope of which invention will be indicated in the claims.Reference should be had to the following detailed description taken inconnection with the accompanying drawing, in which:

Fig. l is a largely diagrammatic showing of the fluid circuits and therelation of the parts to each other and the application of the system tothe gaging of an article;

Fig. 2 is a fragmentary view showing the front face of the indicator ofFigure l;

auals Patented Jan. 29, 1957 ICC Fig. 3 is a view of the particular'gaging nozzle shown in Figure 1 taken at 90 to the cross section ofFigure 1 and adapted to show certain fluid escape passages; and

Figs. 4, 5, 6 and 7 are more or less diagrammatic il-` lustrations ofthe application of the system including the use of appropriateparticular gaging nozzles, to the checking of different articlesrespectively.

The present apparatus employs certain features which may be similar tocorresponding ones shown in the prior Patent No. 2,513,374 in which Iamthe patentee jointly with Clifford Stead. The system is shown hereinin diagrammatic form for the most part since it is the principles andthe combination and relation of the parts and fluid passages which areof particular importance rather than structural details. It will beunderstood accordingly4 that the system may be embodied in a compact4device similar in external appearance and in many structural features tothat disclosed in Figures 3 to l2 inclusive of the above patent. Thecomplete system as shown in Figure 1 includes a source of supply offluid under pressure such as that indicated by the conduit 10 whichdelivers the uid such as compressed air to the regulator valve shown at11 provided with a pressure adjustment knob 12. The device 11 mayinclude a suitable filter means. From the regulator 11 the air isdelivered into conduit 13 at the predetermined desired pressure inaccordance with the setting of the regulator. The conduit 13 has twobranch lines 14 and 15 in parallel, each delivering to an independentventuri meansincluding the constrictions 16 and 17 respectively. Fromthe constriction 16 the air ows through conduit 18 into a gage block 19,as shown in Figure l, and from the constriction 17 the air flows througha conduit 20 into independent passages in the gage block 19. One of thelines 18 or 20 embodies at some point therein a bleed valve such as thatshown at 21 inserted in the conduit 20.

The gage block 19 is designed to utilize the principle of fluid escapefrom an orifice and, as will be noted, the conduit 18 has branch lineswithin the block to orifices 23 and 24 located 180 apart; and conduit 20has corresponding orifices 25 and 26. In the particular application ofthe invention in Figure l, the gaging means is designed for testing thetaper of an article or bushing shown generally at 27. The gage block 19is, of course, of a particular size and taper for the purpose. The faceof the boss 28 in which is located the orifice 23 is located slightlybelow the outer peripheral surface of the block 19 in accordance withthe well known principle of nozzle type gages and the same is true as tothe boss for each of the other nozzles. Suitable passages are providedfor the free escape of the air end-wise of the gaging block such asthose shown at 30 in Figure 3 for the orifice 23 and the passages 31 forthe orifice 25. The amount of air escaping from the respective orificesand correspondingly the velocity in the respective conduits 18 and 20 isdependent, of course, upon the thickness of -the spaces between therespective orifice opening and the juxtaposed inner surface of the boreof the part 27. Y i

Returning to the Venturi means, it will be noted that a branch line 33leads from the constriction 16 and a branch line 34 leads from theconstriction 17. In accordance with the principle of such Venturi meansthe pressures in the pipes 33 and 34 will vary in accordance with thevelocity of air in the respective conduits which in turn is dependentupon the amount of escape clearance for the orifices-of thecorresponding conduits. The respective conduits 33 and 34 are connectedto opposing faces of a differential pressure diaphragm means inaccordance with any suitable arrangement. The diaphragm means may be inthe form of a bellows and accordingly" in the present illustration thepipe 34 leads to the interior of an expansible bellows 35 and the pipe33 leads to the aardige interiorA of a closed casing36 surrounding thebellows so that the pres-*sure from pipe 33 is applied to the outersurface of the bellows 35. Accordingly the stem 37 connected to thesurface of the bellows moves longitudinally in accordance with thedifferential of the pressures applied to the bellows 3 5. This movementof the pin 37 is ampli'- tied and translated into movement of anVindicator of a es'ife'd appropriate character. Asshown somewhatdiagrammatically herein the friec'lianism isy similar to that: shown inthe aforesaid Patent No. 2,513,374 includes a bar 38 rotatably mountedon center pivots at the ends thereof, the bar having a radial arm 39 towhich the pin 37 is connected so that longitudinal movement of the pinrotates the shaft 38. The shaft 38v hassecured thereto another radialfinger 40which is adapted to bear against an edge of segmental gear 41pivoted on shaft 4.2. The segmental gear 41 has teeth meshing with thepinion 43 to rotate shaft 44 on which` is mounted the pointer 45operable over the dial 46, as shown particularly in Figure 2.

In the normal operation of the device, therefore, in

testing the tapered bore of the bushing 27 the effect ofl the clearancesat the orifices 2 3 andl 24l will be applied through the Venturi 16 tothe external surface of the bellows 36 and the effect of the clearancesat the` orifices 25 and 26will be appliedy through the Venturi 17 to theinterior of the bellows 35. These factors are applied as opi posingpressure forces on the diaphragm means of the differential indicatorandthe resultant is directly indicated on the dial thereof and itbecomes in effect a computing indicator. lt will be understoodvfrom aconsideration ofv the principles and operationof the device that thefactor ofthe absolute diameterswithin the bore of the part being gageddoesnotV affect the final result. In other words the effect of variationin diat'ncte'risA applied to both sides of the differential measuringlmeans and the gage reading is a direct measure of the accuracy of thetaper. For example, if the total of the clearances at the orifices 23and 24 equals the total ofthe clearances at the orifices 25 and 26, theforces will be equal and if the gage has been properly pre-set a. zeroreading will be obtained regardless ofthe exact values of thoseclearances. It should be borne in mind that theclearances as shown inthe drawings are exaggerated for the sake of clarity.

Before starting the checking of articles the system will, of course, beappropriately adjusted. For this purpose a standard test part will beapplied to the gaging nozzle 1,9 in place of the article 27 heretoforereferred to andk by manipulation ofthe bleed valve 21 the indicatoradjusted to the zero position as shown in Figure 2. Also, the initialpressure may be adjusted through valve means 11 to vary the sensitivity.The dial may have thereon adjustable pointers 47 positioned to indicatethe tolerance limits in the subsequent testing of the taper ofsuccessive articles 27.

The system illustrated in Figure lfis readily applicable to the checkingof various articles' todetermine the relation of surfaces or parts ofwhich Figures 4, 5 and 6 show additional typical examples. In Figure 4itis utilized to test the cylinder 50`for squareness between the bore 51and the end face` 52. In this gaging nozzle the air conduits 18 and 20.are connected to a'staggered orifice arrangement. Conduit 18, forexample, isfco'nnec'ted to orifices 53 and 54, and conduit 2fl`toorifices 55 and 56. The gage block embodies-suitable passages for thefree escape of the air after flowing away from the boss surrounding therespective orifice as explained in connection with the gage block ofFigures 1 and 3. For example, the air from orifice 5 6 may escapethrough longitudinally extending channels 57, and air'frorriorifice V53may escape through channel`53. The yexample of'Figure 4 illustraties acylinder in which the borefi"salsstained'A tfbe non-perpe'nlriicularv toface'rSZi'suech that, in ythe retated. position'of'the cylindershownipthertotal of the'clearancesA at Athe ends of orifices 55; andisflessQtfhan the total Vof the clearancesat' the "of c/Srficesf51,37.vandfl." In the drawings.. all clearances are of course shown in greatlyexaggerated form in the interest of clarity. The difference inclearances just referred to will produce a certain differential ofpressure and be registered correspondingly on the dial. Rotation of thework piece 50 will of course produce a variation in the reading on thedial as the clearances at the respective orifices change. It is notedthat here again the effect of the diameter ini absolute terms iseliminated from the gagingresults and the gage comprises in effect acomputing indicator vand gives a direct reading of the relativesquareness of the bore to the end face. If one or more conventionalsingle circuit indicators Were employed each indicator reading wouldinclude as a factor the absolute diametral dimension at that point.

In Figure 5 the system is applied, with the use of an appropriate gageblock 60, to the checking of concentricity between two internalcylindrical portions of an article 61 having an internal bore of steppeddiameter defined by the surfaces 62` and63. If an eccentricity existssuch that for example in the rotary position selected the sum of theclearances of the two staggered orifices connected to conduit 11,8v isgreatervas illustrated than that of the two staggered orifices connectedto the conduit 20, the differential effect will be registered on theindicator and the reading will be a measure of the eccentricity whichwill e independent lof the diametral dimensions.

AnV application of the system to the checking of the fit or clearancesbetween the corresponding dimensions of mating parts is illustrated inFigure 6. In this figure the diameter of a cylinder 65 and the bore of amating part 66 are being checked for clearance. One of the parts 6,5 or66 should be of known standard size, and the system then indicateswhetherthe other part being tested has an appropriate mating size.Conduit 18, for example, is connected in gage ring 67 to opposedorifices therein, and conduit Ztl'` is connected in gage plug 68 tooppose orifices therein. The air velocity in conduit 1S, therefore, is atneasure ofthe diameter of the cylindrical part 65, and the velocity inconduit Ztl is a measure of the diameter of the bore in'part 66. Thesetwo factors, however, are applied differentially to the computingindicator and the reading is a direct measure of therelation of therespective diameters. It may be noted in this regard that anyeccentricity between the cylindrical part 65 and its gage 67, or betweenthe bore in part 66 and its gage plug 6,8 is of substantially* no effectsince the total of the clearances at the particular pair of orificesremains the same.

Figure 7'ithe `system is applied to the checking of the center distancebetween a pair of openings 70 and 71. into which extend the plugportions 72 and 73 respectively of the gage4 block 74. If the sum of theclearances at orifices 75wand V76 connected to conduit 18 is differentfrom the sum of the clearances at the orifices 7.7 and 78 it willregister on the indicator and the displacement from zero reading willcomprise a direct reading of the departure of the center distances ofthe openings 70 and '71 from the prescribed standard.

Since certain changes may be made in the above construction anddifferent embodiments of the invention could be made without departingfrom the scope thereof, it is intended that all matter contained in theabove description or shown in the accompanying drawing shall beinterpreted yas illustrative and not in a limiting sense.V

I claim: i

l. inl a fluid gage apparatus, in combination, a source of fluid underpredetermined pressure, a pair of conduits connected thereto, a gagingmeans including a gaging nozzle mounted in a gaging body connected toeach of said conduits, va Venturi means in each of'said conduits, and.an indicator provided with a' fluid connection into each of saidVenturi means'andV arranged to respondl to the differential pressures*thereof in accordance with the respectiveV fluid'velocities. n

V2. in' a fluid gage apparatus, in combinahon, a pair :of conduitsadapted to conduct fluid in parallel, means for supplying uid underpredetermined pressure to each of said conduits, a gaging meansincluding a gaging nozzle mounted in ya gaging body connected to each ofsaid conduits adapted to be applied to articles to be gaged, a Venturimeans in each of said conduits, an indicator provided with a iiuidconnection into each otsaid Venturi means and arranged to respond to thediierential pressures thereof in accordance with the iiuid velocities inthe respective conduits, and a iiuid bleed valve in one of said conduitsbetween its gaging nozzle means and Venturi means to vary the iiuid flowin said conduit and the setting of said indicator.

3. In a gaging apparatus adapted to employ the principle of variationsin iiuid escape from an orice into a space between the surface of anarticle being tested and the orifice, the combination of a first tif-aidconduit, u first gaging means including a gaging nozzle mounted in agaging body connected thereto adapted to be applied to the testing ofthe space provided between the orifice and a certain surface of anarticle, a second iiuid conduit in parallel with the iirst, a secondgaging means including a gaging nozzle mounted in a gaging bodyconnected to said second conduit adapted to be applied to the testing ofthe space provided between the orifice thereof and another surface of anarticle related to the tirst mentioned surface, means for supplyingfluid under predetermined pressure to each of said conduits, a Venturimeans in cach of said conduits, an indicator provided with a liuid connnection into each of said Venturi means and arranged to respond to thedifferential pressures thereof in accordance with the iiuid velocitiesin the respective conduits and thereby to indicate the relation of thespaces being tested and accordingly of the relation of said surfaces.

4. In a duid gage apparatus, in combination, a pair of uid conduits, arst gaging means including a gaging body having an air escape meanstherein connected to a first one of said conduit-s, a second gagingmeans including a gaging body having an air escape means thereinconnected to the other of said conduits, the respective gaging meansbeing arranged for the testing of different dimensions, means forsupplying iiuid under predetermined pressure to each of said conduits,intermediate means in each of said conduit-s including a branch line forproducing in said line a iiuid pressure variable in accordance with theuid flow in the respective conduit, an indicator including a diaphragmmeans, said branch lines being connected to said diaphragm means in amanner to direct the pressures thereto in an opposed relation wherebysaid indicator is responsive to the differential eiect thereof andthereby of the variations of the different dimensions, and an adjustablebleed valve in one of said conduits between said gaging nozzle means andsaid intermediate means thereof to vary the eiect on said indicator andadjust the setting thereof.

5. In a gaging apparatus employing the principle of uid escape from agap, the combination of, a first uid conduit, a iirst gaging meansincluding a gaging body having an air escape means mounted thereinconnected to said first conduit adapted to be applied to the measurementof a certain transverse dimension of an article, a second fluid conduitin parallel with the first, a second gaging means including a gagingbody having an air escape means connected to said second conduit adaptedto be applied to the measurement of a different transverse dimension ofan article related to the first mentioned dimension, means for supplyingiiuid under predetermined pressure to each of said conduits, means ineach of said conduits including a branch line for producing in saidbranch line a fluid pressure variable in accordance with the fluid flowin the respective conduits as determined by the air escape at therespective air escape means, and a single indicator including a iiuidpressure responsive means and a movable indicator element connectedthereto, said pressure responsive means being so constructed and saidbranch lines being connected thereto in a manner whereby variations inthe two measurements and thereby of the respective escape gaps for thetwo conduits produce opposite eiects on the pressure responsive meansand the indicator registers the differential effect thereof.

6. In a gaging apparatus adapted to employ the principle of variationsin fluid escape at an escape gap, the combination of a first iiuidconduit, a irst gaging means including a gaging body having an airescape means therein connected to said first conduit adapted to beapplied to the measurement of a certain transverse dimension of anarticle, a second fluid conduit in parallel with the rst, a secondgaging means including a gaging body having an air escape means thereinconnected to said second conduit adapted to be applied to themeasurement of another transverse dimension of an article related tosaid certain rst dimension, means for supplying fluid underpredetermined pressure to each of said conduits, a single indicatorincluding a flexible diaphragm means and a movable element connectedthereto, said indicator being provided with a iiuid connection into eachof said conduits, the pressure in the respective connections varying inaccordance with the fluid liow in the corresponding conduit asdetermined by the escape at the corresponding air escape means and saidfluid connections being arranged to direct the pressures therein to saiddiaphragm means in opposed relation whereby the indicator is responsivetothe differential elect of the variable pressures in said connectionsand the indicator registers directly the relation of the two dimensions.

References Cited in the le of this patent UNITED STATES PATENTS1,162,475 Gibson Nov. 30, 1915 1,803,260 Kondo Apr. 28, 1931 2,513,374Stead et al. July 4, 1950 2,573,843 Hendrix et al. Nov. 6, 19512,594,046 Mahlmeister Apr. 22, 1952 2,594,077 Schulze Apr. 22, 19522,665,579 Fortier Ian. 12, 1954

